UML中继承实现依赖关联聚合组合的联系与区别_线条箭头 http://wenku.baidu.com/link?url=ZjlPxyZtoxkdP3ecIACq8HS46EQJWET9UIMgRPrYVMZRRPrY9WPLzhMaEIQBgaLPsJLrXXvJeUFifzps5aendwS63lRlyd41gnxgkmILksy